[d4700]

Figured I'd post this since I didn't see any guides online specifically for the hybrid variant of this transmission. The job is mostly the same if you've done it on any other 6HP or 8HP, but there are some unmentioned oddities I've found in this process that I thought I'd share here.

The pan I used is a Hengst unit I got from RockAuto for $110+$16 shipping. An excellent deal. I used Valvoline Extended Protection ATF (Using the "MaxLife" ATF/CVT fluid makes me a bit antsy. Why would I want steel-steel friction modifiers in my step-shift auto?). My transmission took in a little over 6 quarts, so it's not a bad idea to just buy two gallon jugs of the stuff.

CAUTION - HIGH VOLTAGE. Do NOT work on your car while it is charging. Do NOT mess with any bright orange cables or modules with the caution tag on them. Be careful with your tools. BMW insists that you disable the HV system before carrying out this job, so you should do that.

1. Level your car on jack stands. Remove the handful of 8mm bolts holding the service tray directly below the transmission. Remove the tray and toss it to the side. Make sure not to lose any of the white plastic bits that clip onto it.

2. Open the fill plug slightly. It's to the right of the drain plug, next to the exhaust pipe. You'll need a stubby 8mm hex key to do this - I just used my Dremel and shortened the head so that it would fit. It's tight! We're just trying to make sure you can get it loose before you drain the fluid, so don't pull it all the way out yet.

3. Now open the drain plug. It's a 10mm hex. Have a big pan ready, it'll fan the fluid out into a pretty wide pattern. It's not a bad idea to measure the amount of fluid that comes out to make sure you're on the right track.

4. Remove the 15 or so T40 bolts holding the transmission pan up. It's a good idea to have an oil mat or some cardboard set down on your garage floor here, as this can get messy. Pull the pan straight off and make sure the O-rings on both of the pickup tubes came with it. Now just look at all that gunk!

5. Get your new pan and oil the O-rings for the e-pump and mechanical pump pickup tubes, just to make sure they slide in nice and easy. Push it straight up and, when the pan is flush with the transmission and lined up with the bolt holes, you're good to go. Don't force it!

6. Following this torque sequence, first hand-tighten the bolts, then torque them down to 10nm (~88 in*lb).


7. Once the pan is on, remove the fill plug and pump in some ATF until it drips out. In my case, it took about a gallon. This is your first fill.

8. Get in your car and start it in electric mode. Let it rest for about 10 seconds, then select D, then R, each for 10s. Make sure the parking brake is on and your foot is firmly on the brake. This runs the electric fluid pump. Shut off the car.

9. Get back underneath and pump in more fluid until it drips. I think mine took in another quart.

10. Last step - open your hood, then start the car. The engine will run. Get underneath and fill the fluid until it drips, and once the fluid is between 30-50C (as read through OBD port) and dribbling out, close the fill plug. Shut off the engine.

11. Nice work! Wipe off all the excess fluid, check for leaks, and put the service tray back on.